Combination back pressure and vacuum relief valve



Jan. 17, 1928. 1,656,349

M. E. GARRISON COIB INATION BACK PRESSURE AND VACUUI RELIEF VALVE FilQdFeb. 18, 1924 raga 5 ,56 m 27 H 29 I7 23 26 WI/iZ/ITOQ: MURFFAY E.Gnmwsorv ATTOENL'YF- Patented Jan. 17, 1928. 1,656,349

UNITED STATES RATENTOFF-ICE.

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I Application fled February 18, 1924. Serial No. 608,788.

This invention relates to relief valves in The especial advantages ofthe invention tended for controlling pressures within reand furtherobjects thereof will be made eviis ceptacles and has its particularapplication 'dent hereinafter. I in the oil industries in the mannerherein- Referrmg to the drawing which is for il- 6 after described.lustrative purposes only:

Although the device may be employed on Fig. 1 is an elevational viewshowing a tanks in which various other liquids are ankequlppcd with anembodiment of my inso stored, the single ap lication thereof to oil -istorage tanks will y demonstrate the util F 1g. 2 1s an'enlarged planview of the reity'of the invention. Crudeoils as delivered i f valve.

from the well contain large uantities of vol- F ig- 3--'is a Sectiontaken on a plane repatile material such as the ighter fuel hynted'by thehne 33.of 2.

drocarbons. In order to prevent pressures As shown m the drawing,einvention ithi thgt-ank hi h mi ht prove destrucemploys a tubular shell11" preferably contive, it is customary to provide a small ventstructe'd Of ligh metII-lplat'es and dispose the interior of the tank isthe same as the n opening in the storage tank through which withtheaxigA-lh thereof in substantially gas may escape. It .will berecogmzed that g t fl-l posltlon. For the purpose of ro- 70 h an open ti d, th pressure on vidmg commumcation between the she] 11 t e storagetank 12, an elbow 14 is emsurrounding atmospheric pressure. I ployedhavin a flange 15 on' the down- Many of the volatile-hydrocarbonsevapowardly extol! i g eg thereof'whereb atrate very slowly in the airand still more tachment y be made o a saddle nge I slowly :when underpressure; By placing a t n ing means 16 secured in the pressure on thesteragetanks, it is ssibleto P 0f the tank The lateral 18 17 0f amaximum quantity of v0 gtile eonthe elbow 14 OOHDGOtS directl illtQt eshell stituents in the oil. The invention provides 1 at a oint slightlybelow t e center therea means whereb afpreaure is contmuonsly own sothat the lower ed 18 of so i t i d i t t k, thi re b i g the pipe 17is'but a short distance m the regulated so, a n t t x eed 1; a stre gthor loweredfe 19 of the shell 11; -A valve seat resistance of the tank,The ex- 13 provl d; in thG lower end of the tubular erted, however, issuflicient to considerably. member 11,'th1s valve seat being in the formreduce evaporation. a of a ring 21 having an annular gasket 22 5 Seriousstrains are often placed on oil storof wool felt or other similarmaterial se .tanks when they are being filled or dis- 9 9 the 25: filmthemof y 8' secur- 0 ar due to the fact that the small vent mg ring 223.u per opening of the whi iscommonly employed is too. small to member 11-1s equippe with a valve seat 25, permit a free flow' of airtherethroulglh, thus onslstlng of 'asuEeporting 26 having so :cexcessive pressuresintheta when. a wool gasket mem r 27 secu on the uoilj pumped thereinto at high veper face thereof by a ring 29. Contraand dangerous conditions of vacuum wlthl'n the tubular memberll, thereexten s .whi tend to collapse the tank when the oil a gulde member 30consisting simply of a is being discharged therefrom.- Theinvenvertically positioned pipe 31 supported by tion provides a specialform of valve having a piple 3?, welded thereto as indicated at 33 aclosure member arranged to open outwardand aving the end 34 thereofflattened and grand. to allow the discharge of gas there! bent intovertical extension so as to be bolted The valve also provides a closureplate arcircular plate 38 is a ranged ugh when the internal premurewithin as shown at 85 to the member 11. An up r the tank exceeds a predesignated safe value. valve closure member 37 o a torestinodge to openinwardly when the condition engagement on the r 1 t 27, as shown,

59 of vacuum within the tank due to'oil being, and has a stem 40gdownwardly therefrom exceeds a from the center thereof into theupper-end -valu'e which is calculated om maaivenen of structure of thestorage tank. the plate 38 relative to the valve e of the tubular guide'30, which'serves to 10! opening and to hold it in substantial hori'zontal position. A lower closure p ate 43 rests on the gasket 22 and hasa stem 44 extending upwardly into the lower end of the member so as tobecentralized and guided thereby.

Steel tanks will resist varying internal and external pressuresaccording to the strength of the structure. The safe internal pressurefor the tank is determined and the weight of the closure member 37designed accordingly. The external pressure which the tank will safelyresist is also computed and the lower closure member designedaccordingly. Y

It will be noticed that the shell 11 is of larger diameter than the pipe17 and the vertical leg of the elbow 14, thus enabling the making of thevalve openings through the valve seats of the same diameter as theopening throu h elbow members. When the tank is being led with oil whichgenerally occurs at high velocity, the air and gas therein arecompressed by the rising level of oil, overcoming the resistance due tothe weight of the closure member 37 which forces this member upwardly,and escape through the upper valve opening, the upward movement of theplate 38 being limited by bracket arms 50' bolted or otherwise securedin the position shown. When the exit of air and gas stops, the plate 38drops back against the valve seat 37 and prevents further passage andholds a pressure on the interior of the tank. If due to hightemperature, the evaporation of volatile materials should becomeexcessive and the pressure thereof exceed the predetermined value, theclosure member 37 will be raised by the internal pressure, thus allowingthe gas to escape.

V ordinary storage tank either due to the discharge of oil therefrom ordue to change in temperature causing condensation of vaporizedhydrocarbons. When the condition of vacuum within the tank exceeds theresistance of the plate 43, it will be raised as indicated. by thedotted lines 55, Fig; 3, thus allowing the entrance of air into thetank. The valve opening provided by the valve seat 21 is of ample sizeto care for an intake of air equal to or greater than the dis charge ofthe oil from the tank. In event, that it is desired to place additionalpressure on the interior of the storage tank, weights may be employed onthe closure member 37 as indicated by the dotted of the outlet valveagainst being opened by internal pressure. the upper face of the valveseat 21 1s situated on or above the level of the lower edge 18 of the pi17 so that any liquids condensing wit the member 11 will be may be formewardly into lower end of said lines 56, thus affording agreaterresistance I t will be noticed that" drained into the tankthrough the elbow 14 and will, therefore, in no way efiect the ac tionof the lower valve member 43.

Substantially all parts of my novel valve thereof ma be securedtogether'by soldering or wel g, or riveting, light construction beingfavorable to manufacture and sale at a comparatively low. price. My useof wool felt in the gaskets 22 and 27 is especially advantageous onaccount of the fact that this material retains its resilienc or lifeeven when exposed to oil in either vapor or liquid form.

Although, I have herein described one complete embodiment of myinvention, it will be understood that various features thereof might beindependently employed and also that various modifications might be madeby those skilled in the art, without the slightest departure from thespirit and scope of my invention as the same is indicated above and inthe following claims.

I claim as my invention:

1. In a device of the character described, the combination of: avertically disposed tubular member; a pipe member connecting in the sideof said tubular member, for com.- munication with a sto tank; anoutwardly disposed valve seat at the upper end of said tubular member;an inwardl disposed valve seat atthe lower end 0 said. tubular member,the face of said inwardly disposed valve seat being above the level ofthe lower edge of said connecting ipe; a closure member for said upperva ve seat arranged to open under an internal pressure in excess of apredetermined value; and a closure member for said lower .valve seatarranged to open under a reduced internal pressure of a predeterminedvalue. Vacuum conditions may be caused in the 2. In adev1ce of thecharacter described, the combination. of: a vertically disposed tubularmember; a pi member connecting in thefside of said tu ular member, forcommunication with a storage tank; an outwardly dis sed valve seat atthe up r end of said tu ular member; an inwa y disosed valve seat at thelower end of said tuular member, the face of said inwardly disposedvalve seat bein above the level of the lower edge of sai connectingpipe; a guide member axially disposed in said tubular member; an uppervalve plate having a stem extending downwardly into the upper end ofsaid guide member; and a lower valve platehaving a stem extending updemember.

3. In a device of the character described, the combination of: avertically 0 s f bular member; a pipe member connecting in the side ofsaid tubular member, for communication with a storage tank; anoutwardldisposed valve seat at then per-rend of ai tubular member; an inwa ydisposed valve of sheet metal, and the parts 10 Ill seat at the lowerend of said tubular member; a guide member axially disposed in saidtubular member; an upper valve plate having a stem extendin downwardlyinto the upper end of said gui e member; and a lower valve plate havinga stem extending upwardly into lower end of said uide member.

4. In a device o the character described, the combination of; avertically disposed tubular member; a pipe member connecting in the sideof said tubular member, for communication with a storage tank; anoutwardly disposed valve seat at the u per end of said tubular member;an inward y disposed valve seat at the lower end of said tubular member,the face of said inwardl disposed valve seat being above the level 0 thelower edge of saidconnectin pipe; a clesure'member for said upper va veseat arranged to 0 en under an internal pressure in excess 0 apredetermined value; and a closure member for said lower valve seatarranged to open under a reduced internal pressure of a predeterminedvalue, said tubular member and-

